1. Field of the Invention
The present invention pertains to the art of cooking and, more particularly, to a fan assembly provided in an oven cavity of a convection cooking appliance.
2. Discussion of the Prior Art
Conventional cooking appliances generally perform cooking operations through radiant heating developed from bake and/or broil elements. Such types of cooking appliances can take various forms, mainly ranges and wall ovens. Some radiant cooking appliances incorporate internal fans which can be used during certain cooking operations in order to generate an air flow within an oven cavity to enhance even cooking. Therefore, known cooking appliances can perform convection cooking operations. Convection cooking is actually prevalent in microwave and other types of ovens as well.
In convection cooking appliances, the air flow can be designed to recirculate within the oven cavity, flow through the oven cavity and be exhausted, or a combination of both of these configurations. For obvious reasons, it is desirable to enhance the efficiency of any air flow system in order to reduce associated operating costs, while minimizing the required fan size in order to produce an effective air flow rate. In addition, the manufacturing and assembly costs related to producing and installing an air flow system is of concern. Therefore, regardless of the existence of numerous convection systems in the art, there is always a need for an improved convection air flow system for use in a cooking appliance.
The present invention is directed to a fan assembly for a convection cooking appliance. Preferably, the cooking appliance includes a oven cavity and one or more heating elements for the oven cavity, while the fan assembly functions to develop a recirculating air flow within the oven cavity for convection purposes. In accordance with the invention, a recirculation fan assembly, preferably of the centrifugal type, is provided wherein air is drawn in along a central axis and expelled outwardly in a radial direction. The fan is essentially constituted by a rotating plate having blades which extend axially therefrom a relatively short distance.
Mounted over the fan is a cover or shroud which lies in relatively close proximity to the fan blades. About the outer periphery of the cover are arranged numerous exit holes to provide for exhaust and, at the center of the cover, a circular, unobstructed intake hole or opening is provided coaxial with the fan itself. This opening also has an associated diameter. Spaced a short axial distance from the opening within the fan housing, there is a circular zone which defines a fan inlet where no blades are present. In accordance with the invention, the opening is unobstructed and preferably circular, with the diameter of the opening in the fan cover not exceeding the diameter of the fan inlet. However, regardless of the actual shape of the opening, the area of the opening in the fan cover is equal to or larger than the sum of the cross-sectional areas of the mating fan as defined between the fan blades as air enters the blades.
Although the invention could be applied to both electric, gas and microwave cooking appliances, the most preferred embodiment of the invention takes the form of an electric range or wall oven. In any event, additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings wherein like reference numerals refer to corresponding parts in the several views.